#include <iostream>

using namespace std;

int linearsearch(int array[], const int, int);

int main() {
	const int size = 5;
	int array[size] = { 5, 15, 6, 9, 4 };
	int search = 4;

	int ans = linearsearch(array, size, search);

	if (ans != NULL) {
		cout << "Element " << search << " present at index " << ans;
	}
	else {
		cout << "Element " << search << " is not present in array";
	}

	return 0;
}

int linearsearch(int array[], const int size, int search) {
	if (size == 0) {
		return NULL;
	}
	else if (array[size - 1] == search) {
		return size - 1;
	}
	else {
		linearsearch(array, size - 1, search);
	}
}